Claims:We claim:

1. A vehicle comprising:
a pre charge module (104), the pre charge module (104) includes:
a plurality of pre charge resistor (201);
a plurality of one-way switch (202);
a plurality of isolators (203);
a plurality of relay drivers (204); and
a sensing mechanism (not shown) to initiate pre charging of a pre charge capacitor (not shown) prior to starting of a traction motor (103) for a single ground or an isolated ground pre charge module (104).
2. The vehicle as claimed in claim 1, wherein the pre charge module (104) being integrated with one of a vehicle control unit (101), a motor control unit (102), and a battery management system (not shown).
3. The vehicle as claimed in claim 2, wherein one of the vehicle control unit (101) and the motor control unit (102) being configured to control the plurality of relay drivers (204) in the pre charge module (104).
4. The vehicle as claimed in claim 1, wherein the pre charge module (104) includes a pre charge line (106) being controlled by a first relay driver switch (108) which is further configured to be connected to one or more power source (100).
5. The vehicle as claimed in claim 1 or claim 4, wherein the pre charge module (104) includes a main supply line (105) being configured to be connected to the one or more power source (100) and the motor control unit (102) and being operated by a second relay driver switch (109).
6. The vehicle as claimed in claim 1, wherein the pre charge module (104) being operatively connected to the motor control unit (102), the motor control unit (102) being connected to the traction motor (103).
7. The vehicle as claimed in claim 1 or claim 5, wherein the pre charge module (104) includes the sensing mechanism (not shown) which includes one or more sensing points to isolate single or isolated grounds.
8. The vehicle as claimed in claim 1 or claim 7, wherein the pre charge module (104) includes the pre charge resistor (201) configured to receive power from the main supply line (105) and the pre charge resistor (201) being connected to the one-way switch (202) which provides direction to the current flow path to the pre charge line (106).
9. The vehicle as claimed in claim 8, wherein the one-way switch (202) being a diode.
10. The vehicle as claimed in claim 1 or claim 8, wherein the sensing mechanism (not shown) of the pre charge module (104) includes the plurality of isolators (203) to isolate the connection between the single ground system and the isolated ground system.
11. The vehicle as claimed in claim 10, wherein the plurality of isolators (203) being connected to a digital logic unit (205) which gives input to the plurality of relay drivers (204) based on the signal provided by the plurality of isolators (203).
12. The vehicle as claimed in claim 11, wherein the plurality of relay drivers (204), based on the input given by the digital logic unit (205) cuts off the pre charge module (104) and allows the traction motor (103) to run independently throughout the vehicle running condition.
13. The vehicle as claimed in claim 1, wherein, the pre charge module (104) communicates with the vehicle control unit (101), the traction motor (102) and the motor control unit (102) through a CAN communication.
14. A method to pre charge a pre charge capacitor (not shown) of a motor control unit (102) using a pre charge module (104), the method comprising the steps of:
sensing by the pre charge module (104), an ignition ON condition indicating first voltage at a power source (100) side terminal, (at step 300 and 301);
verifying by the pre charge module (104), whether a sensed value of the first voltage at power source side terminal being greater or equal to a first pre-determined value of voltage of a power source (100), connecting the motor control unit (102) to the power source (100) through the pre charge module (104), (at step 302);
initiating charging of a pre charge capacitor (not shown) of the motor control unit (102) by the pre charge module (104), if the sensed value of the first voltage at the power source side terminal being greater or equal to the first pre-determined value of voltage of the power source (100);
sending by the vehicle control unit (101), a charging status of the pre charge capacitor (not shown) to the motor control unit (102), and receiving an acknowledgement message for full charging status from the motor control unit (102), when the pre charge capacitor voltage reaches to a second predetermined voltage value of the pre charge capacitor (not shown), (at step 303 and 304);
opening and closing by the pre charge module (104), a first relay driver switch (108) and a second relay driver switch (109) simultaneously to connect the motor control unit (102) to the power source (100) directly via a negligible resistance path, upon receiving the acknowledgement message from the motor control unit (102), (at step 305);
sensing the pre charge capacitor voltage level by the vehicle control unit (101) continuously; and
disabling a user input by the motor control unit (102), if the pre charge capacitor voltage fails to reach to the second predetermined voltage value of the pre charge capacitor (not shown) within a predefined time interval, upon intimation of the vehicle control unit (101), (at step 306).
15. The method to pre charge the pre charge capacitor (not shown) of the motor control unit (102) as claimed in claim 14, the method comprising the steps of:
restricting by the pre charge module (104), a charging current to the pre charge capacitor (not shown) in the motor control unit (102), configured for controlling ripple power of the motor control unit (102) during DC to AC conversion; and
disconnecting the pre charge module (104) from the power source as well as (100) the motor control unit (102) by itself, after the completion of pre charge.
, Description:TECHNICAL FIELD
[0001] The present subject matter relates to a vehicle. More particularly, to a pre charge module of a vehicle.

BACKGROUND
[0002] Now-a-days, there is an ever-increasing crisis of fossil fuels and subsequent increase in cost of the fossil fuels, which has led to the demand of alternative vehicles. Subsequently, an electric vehicle and a hybrid electric vehicle are the viable options. However, the electric vehicles and the hybrid electric vehicles require high power input and a high-capacity motor to run at optimum efficiency which often burdens the running capacity and the health of the motor. Hence, an adequate means to support the function of the motor is needed which also prevents any adverse effect on health of the motor in high-capacity operations.

BRIEF DESCRIPTION OF THE DRAWINGS

[0003] The present invention is described with reference to a circuit diagram, block diagram and a flow chart. This invention is implementable in two-wheeled vehicles/three-wheeled vehicles or four-wheeled vehicles. The same numbers are used throughout the drawings to reference like features and components. Further, the inventive features of the invention are outlined in the appended claims.
[0004] Non-limiting and non-exhaustive embodiments of the invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified.
[0005] The details are described with reference to the accompanying block diagram, circuit diagram, and flowchart. The same numbers are used throughout the drawings to reference similar features and components.
[0006] Figure 1 exemplary illustrates a block diagram of a vehicle with a precharge module, as per embodiment, in accordance with one example of the present subject matter.
[0007] Figure 2 exemplary illustrates a block diagram of an internal circuitry of a pre charge module, as per embodiment, in accordance with one example of the present subject matter.
[0008] Figure 3 exemplary illustrates a flowchart explaining the charging of a pre charge capacitor by the pre charge module, as per embodiment, in accordance with one example of the present subject matter.

DETAILED DESCRIPTION

[0001] In the following description, it is contemplated that the disclosure in the present invention may be applied to any vehicle without defeating the spirit of the present subject matter. The detailed explanation of the constitution of parts other than the present invention which constitutes an essential part has been omitted at suitable places.
[0002] Conventionally, in an electric vehicle or a hybrid electric vehicle, a motor control unit is connected to a motor. In order for the motor to function safely, when the ignition is switched ON, the power components in the motor control unit must be charged and the charge is then used to run the motor which in turn runs the vehicle. If the motor control unit is not pre-charged, there can be huge uncontrolled influx of current from the battery. This huge influx of current in turn can damage the battery, or burn the wiring harness or in turn damage the motor control unit itself. Hence, before driving the motor, the motor control unit must be pre-charged. The motor control unit contains a large value capacitor which provides power during the conversion of DC power to AC power to drive the traction motor. This capacitor is called as a pre charge capacitor. During Ignition ON condition, the battery is switched ON from 0 volt to maximum voltage in a short instant of time creating a huge inrush current to flow from the battery to the motor control unit to charge the pre charge capacitor. At the power ON condition, the motor control unit needs to pre charge the capacitor before starting to drive the traction motor. The motor control unit consists of an inverter to convert DC supply to AC to provide power to the traction motor and the pre charge capacitor to provide instantaneous ripple power to the inverter. The pre charge capacitors are usually huge capacitors generally in terms of 1000th of microfarad to provide required instantaneous power to an inverter circuit.
[0003] The motor control unit is connected to the battery via two lines, a pre charge line and a main supply line from the DC battery. The pre charge line is used to pre charge the capacitor of the motor control unit before it starts driving the traction motor. Sensing of a pre charge status is done by the pre charge module to carry out further required operation. The main supply line from the battery is used to supply required amount of power to drive the traction motor based on the input provided by a user. A pre charge relay is used in the pre charge line to initiate pre-charging of the capacitor based on the status of the ignition signal and other required input such as handshaking from the battery, handshaking from the motor control unit, and the like. The main supply line for motor control unit also contains a relay which is used to supply the battery power to the motor control unit.
[0004] Additionally, in an existing pre-charge system, a pre-charge module is provided with an inbuilt DC-DC converter to reduce power losses during pre-charge. Also, in another type of existing pre-charge module of an electric vehicle, charging of a pre-charging module is carried out with a single ground system. In a conventional pre-charge module comprising a pre-charge resistor and a pre-charge diode, a supply line from a battery is connected to the pre charge resistor functioning as pre-charge for the motor control unit. The pre-charge diode provides a unidirectional path for current to flow from the battery and is further supplied to the motor control unit to charge the motor. Thus, this mechanism is for unidirectional flow of current to the motor control unit for the single ground system.
[0005] Now-a-days, the single ground module is employed for a vehicle with a low battery capacity in which all the vehicular electrical loads are connected to a single ground. Further, single ground pre-charge modules are easy to construct and operate all the control switches responsible for establishing minimum resistance path from the battery and the motor control unit line. However, in high power electric vehicle or hybrid electric vehicle with high battery capacity, requires more than one ground system or an isolated ground system to support heavy vehicle electrical loads.
[0006] In a conventional isolated pre-charge module, there are two ground terminals. In one ground terminal, the battery, the motor control unit and the motor are connected. In another ground terminal an instrument cluster and other vehicle loads are connected. This design helps in optimizing the uniform distribution of current across the motor controller and other vehicle loads. However, in the above-mentioned design, the pre-charge module is located externally to the battery and the motor control unit, and this occupies a lot of space in the already space constrained electric vehicle or hybrid vehicle.
[0007] Hence, there is a need for an improved design of a pre-charge module for a single ground system as well as isolated ground system of a vehicle which is compact in design and overcomes all the above problems & trade-offs as well other problems of the known art.
[0008] As per an object of the present invention, the present subject matter discloses a customizable pre-charge module to be either in-built in the battery module or the motor control unit or to be mounted externally to the battery or the motor control unit.
[0009] It is another object of the present invention to provide an improved pre-charge module which can retrofitted in an existing system with minimum number of modifications in the wiring and is easy to use in single or isolated ground system.
[00010] As per an aspect of the present subject matter, a vehicle comprising a pre charge module is disclosed. The pre charge module includes a plurality of pre charge resistor; a plurality of one-way switch; a plurality of isolators; a plurality of relay drivers; and a sensing mechanism to initiate pre charging of a pre charge capacitor prior to starting of a traction motor for a single ground or an isolated ground pre charge module.
[00011] As per an aspect of the present subject matter, the pre charge module being integrated with one of a vehicle control unit, a motor control unit, and a battery management system.
[00012] As per an aspect of the present subject matter, one of the vehicle control unit and the motor control unit is configured to control the plurality of relay drivers in the pre charge module.
[00013] As per an aspect of the present subject matter, the pre charge module includes a pre charge line which is controlled by a first relay driver switch and is further configured to be connected to one or more power source.
[00014] As per an aspect of the present subject matter, the pre charge module includes a main supply line which is configured to be connected to the one or more power source as well as a motor control unit and is operated by a second relay driver switch.
[00015] As per an aspect of the present subject matter, the pre charge module is operatively connected to the motor control unit, the motor control unit being connected to the traction motor.
[00016] As per an aspect of the present subject matter, the pre charge module includes a sensing mechanism which includes one or more sensing points to isolate single or isolated grounds.
[00017] As per an aspect of the present subject matter, the pre charge module includes the pre charge resistor configured to receive power from the main supply line and the pre charge resistor is connected to the one-way switch which provides direction to the current flow path to the pre charge line.
[00018] As per an aspect of the present subject matter, the one-way switch is a diode.
[00019] As per an aspect of the present subject matter, the sensing mechanism of the pre charge module includes plurality of isolators to isolate the connection between the single ground system and the isolated ground system.
[00020] As per an aspect of the present subject matter, the plurality of isolators is connected to a digital logic unit which gives input to the plurality of relay drivers based on the signal provided by the plurality of isolators.
[00021] As per an aspect of the present subject matter, the plurality of relay drivers, based on the input given by the digital logic unit cuts off the pre charge module and allows the traction motor to run independently throughout the vehicle running condition.
[00022] As per an aspect of the present subject matter, the pre charge module communicates with the vehicle control unit, the traction motor and the motor control unit through a CAN communication.
[00023] As per an aspect of the present subject matter, a method to pre charge a pre charge capacitor of a motor control unit using a pre charge module is disclosed. The method comprises the steps of sensing by the pre charge module, an ignition ON condition indicating first voltage at a power source side terminal; verifying by the pre charge module, whether a sensed value of the first voltage at power source side terminal is greater or equal to a first pre-determined value of voltage of a power source, the motor control unit being connected to the power source through the pre charge module; initiate charging of a pre charge capacitor of the motor control unit by the pre charge module, if the sensed value of the first voltage at the power source side terminal being greater or equal to the first pre-determined value of voltage of the power source; sending by the vehicle control unit, a charging status of the pre charge capacitor to the motor control unit, and receiving an acknowledgement message for full charging status from the motor control unit when the pre charge capacitor voltage reaches to a second predetermined voltage value of the pre charge capacitor; opening and closing by the pre charge module, a first relay driver switch and a second relay driver switch simultaneously to connect the motor control unit to the power source directly via a negligible resistance path, upon receiving the acknowledgement message from the motor control unit; sensing the pre charge capacitor voltage level by the vehicle control unit continuously; and disabling a user input by the motor control unit, if the pre charge capacitor voltage level fails to reach to the second predetermined voltage value of the pre charge capacitor within a predefined time interval, upon intimation of the vehicle control unit.
[00024] As per an aspect of the present subject matter, the method to pre charge the pre charge capacitor of the motor control unit comprises the steps of restricting, by the pre charge module, a charging current to the pre charge capacitor in the motor control unit which is configured for controlling ripple power of the motor control unit during DC to AC conversion; and disconnecting the pre charge module from the power source and the motor control unit by itself, after the completion of pre charge. The present subject matter is further described with reference to accompanying figures. It should be noted that the description and figures merely illustrate the principles of the present subject matter. Various arrangements may be devised that, although not explicitly described or shown herein, encompass the principles of the present subject matter. Moreover, all statements herein reciting principles, aspects, and examples of the present subject matter, as well as specific examples thereof, are intended to encompass equivalents thereof.
[00025] The foregoing disclosure is not intended to limit the present disclosure to the precise forms or particular fields of use disclosed. As such, it is contemplated that various alternate embodiments and/or modifications to the present disclosure, whether explicitly described or implied herein, are possible in light of the disclosure. Having thus described embodiments of the present disclosure, a person of ordinary skill in the art will recognize that changes may be made in form and detail without departing from the scope of the present disclosure. Thus, the present disclosure is limited only by the claims.
[00026] Fig. 1 exemplary illustrates a block diagram of a vehicle with a pre charge module 104, as per an embodiment of the present subject matter. A system for pre charging includes a one or more power source 100, a vehicle control unit 101, a motor control unit 102, a traction motor 103, and a pre charge module 104. The one or more power source 100 is configured to supply power through a main supply line 105 to the motor control unit 102. The power from the power source 100 is configured to be transferred to the motor control unit 102 via two paths. The first path includes the flow of current from the power source 100 through a first switch 108, which goes through the pre-charge module 104, realizing a pre-charge path through a pre-charge line 106 to the motor control unit 102. The second path includes the flow of current from the power source 100 through the main supply line 105 and then through a second switch 109, realizing a low resistance path to the motor control unit 102. Once the pre-charge is done through the flow of current in the first path, the first switch 108 closes and the flow of current takes place directly from the main supply line 105 through the second path having the second switch 109. The motor control unit 102 is configured to supply power to the traction motor 103 for running the vehicle. The vehicle comprises of an interface module called as vehicle control unit 101. The power transferred from the power source 100 to the motor control unit 102 through the pre-charge path includes a plurality of sensing points 206 for the vehicle control unit 101. A power source voltage is sensed by the sensing points 206. In an embodiment, the pre charge module 104 is integrated with one of a vehicle control unit 101, a motor control unit 102, and a battery management system (not shown). In the present embodiment, the pre charge module 104 is integrated with the vehicle control unit 101 and the pre charge module 104 is operatively connected to the motor control unit 102. The motor control unit 102 is further connected to the traction motor 103. The first switch 108 and the second switch 109 are actuated by one or more automated relays and are operated by one of the vehicle control unit 101 or the motor control unit 102. This relay is connected with a plurality of wiring harness at a LOW voltage side configuration of the vehicle. The switches (108,109) are operated only after determining the power source voltage and the pre-charge status. The first switch 108 is normally a closed relay. The second switch 109 is a high side contractor relay responsible for connecting the motor control unit 102 to the power source 100 via a minimum resistance path. The switches (108, 109) can be realized by electromechanical relays or solid-state relays. This operation can be accomplished in the single ground system as well as in the isolated ground system. In the isolated ground system, the power source 100 and the motor control unit 102 are on one ground and the vehicle control unit 101 and the pre-charge module 104 is on a separate ground.
[00027] Fig. 2 exemplary illustrates a block diagram of an internal circuitry of a pre charge module 104, as per an embodiment of the present subject matter. The pre-charge module 104 of the vehicle includes a plurality of relay drivers 204, a digital logic unit 205, a plurality of isolators 203, a plurality of pre charge resistor 201, a plurality of one-way switch 202, and the pre charge line 106. In the present embodiment, one pre charge resistor 201 and a single one-way switch 202 is employed. The one-way switch 202 is a diode. The pre charge resistor 201 limits the inrush current from the power source 100 to the motor control unit 102, once the ignition is ON. The diode 202 restricts the current flow from the motor control unit 102 to the pre charge module 104, once the pre charge action is completed and first switch 108 is operated to open. The plurality of isolators 203 is installed in the pre-charge module 104 which isolates ground configuration and is configured to sense the voltage of the motor control unit 102 and the power source 100. This sensing mechanism of sensing the pre charge voltage and power source voltage, are isolating both the grounds of the isolated ground system. The first isolator 203a senses the pre-charge voltage flowing on the pre-charge line 106 and the second isolator 203b senses the power source voltage flowing on a charge line (not labelled). The sensed pre-charge voltage and the one or more power source voltage by the isolators (203a, 203b) are analyzed by the digital logic unit 205. Further based on the voltages sensed, the switches (108, 109) are operated with the help of the relay drivers 204. The relay drivers 204 actuate the switches (108, 109) by means of a plurality of control lines. Further, the time of charging can be modified up to a safe level by changing the value of pre charge resistor 201.
[00028] Fig. 3 exemplary illustrates a flowchart explaining the charging of a pre capacitor (not shown) by the pre charge module 104, as per embodiment of the present subject matter. When the ignition is in ON condition (at step 300), the first voltage at the power source terminal 100 is sensed by the pre charge module 104 (at step 301). Upon verification by the pre charge module 104 that the sensed first voltage at power source side terminal 100 is greater or equal to a first pre-defined threshold value of voltage of the power source 100 (at step 302), the motor control unit 102 is connected to the power source 100 through the pre charge module 104 and a pre charge capacitor (not shown) starts charging. In the present embodiment, the first pre-defined threshold value should be less than X1 volts e.g. 5 volts to avoid the power source 100 from going into a sleep mode. Once the pre charge capacitor (not shown) voltage reaches to a second predetermined voltage X2 value of the pre charge capacitor, the vehicle control unit 101 sends a charging status to the motor control unit 102 (at step 303) and waits for the receipt of an acknowledgement message for full charging status from the motor control unit 102. Upon receiving the acknowledgement message from the motor control unit 102 (at step 304), the pre charge module opens the first switch 108 S1 and closes the second switch 109 S2 simultaneously to connect the motor control unit 102 to the power source 100 directly through a negligible resistance path which is the main supply line 105 for the motor control unit 102 (at step 305). The pre charge module 104 keeps on sensing the precharge capacitor voltage level continuously. If this value does not reach to the second predetermined voltage value X2 of the pre charge capacitor within a predefined time interval, the vehicle control unit 101 informs the motor control unit 102 to disable the user input via CAN communication to avoid any damage and fault (at step 306). The pre charge module 104 restricts the charging current to the pre-charge capacitor in the motor control unit 102 and controls ripple power of the motor control unit 102 during DC to AC conversion thereby achieving safe operation. After the charging of the pre-charge module 104, it disconnects itself from the power source 100 and the motor control unit 102 so that, the vehicle control unit 101 does not get effected by regeneration, or normal operating current. The plurality of relay drivers 204, based on the input given by the digital logic unit 205 cuts off the pre charge module 104 and allows the traction motor 103 to run independently throughout the vehicle running condition. Many other improvements and modifications may be incorporated herein without deviating from the scope of the invention.

List of reference numerals:
100: One or more power source
101: Vehicle control unit
102: Motor control unit
103: Traction motor
104: Pre charge module
105: Main supply line
106: Pre charge line
107: Ground supply
108: First switch
109: Second switch
201: One or more pre charge resistors of 104
202: One way switch of 104
203: A plurality of isolators of 104
203(a): First isolator of 203
203(b): Second isolator of 203
204: A plurality of relay drivers of 104
205: A plurality of digital logic unit of 104
206: A plurality of sensing points